This invention relates generally to devices for receiving manual user input for control of parameters such temperature, volume, speed, direction, and cursor movement on a computer screen. It relates to the field of computer input devices where joy sticks, mice, and track balls find common usage as pointing devices. The present invention is a tactile device based on analog control and has an output resistance which varies with the force applied to the device. It relates more specifically to an improved device for electronic positional and directional control using a plurality of individual tactile sensors.
Various electronic positional and directional control devices are available that enable a user to control either one or two parameters. An example of one parameter control is the use of up arrow keys and down arrow keys to scroll text in an up or down direction on a computer screen when using a word processor computer program. Touch pads are also used for one parameter control in applications requiring manual control, such as the liquid level in a container or volume from an acoustic speaker system. An example of two parameter control is the use of mice, trackballs, or joysticks to position a cursor or other object in an up and down direction and in a left and right direction on a computer screen. A more recent application is the provision of a miniature joystick in the middle of a conventional computer keyboard. These and similar devices are well known in the art and are generally limited to two parameter control without the addition of hardware and software to provide additional capability. For example, a mouse is capable of two parameter up, down, left and right positioning, but requires a button to provide a third parameter for "clicking" on an object on the computer screen.
Some of the limitations of arrow keys and keypads are the need to reposition a finger to a different location in order to adjust or change direction of the control parameter. A limitation of mice and trackballs is the need for a clean environment and maintenance of the mechanical revolving structure and associated sensing devices. In addition, mice require a surface area on which to move. Joysticks are generally constructed such that a pivoting lateral movement of the vertical joystick is translated into a vertical force on at least four force sensors by four laterally extending arms fixed to the bottom of the joystick. This arrangement requires a relatively complex assembly to provide for the translation of the joystick movement into vertical forces on the force sensors. The translation of the force on the joystick into positional commands requires that there be a force on all sensors to prevent loss of information. In order to prevent this loss of information, a preload spring is required on each sensor. The force sensors used in these various controllers include piezoelectric devices, semiconductor devices, capacitive devices and conductive ink devices. Examples of control devices are described in the following U.S. Letter Pat. Nos. 3,011,063; 4,091,234; 4,493,219; 4,810,992; 5,510,812; 5,541,570; and 5,541,622.
It is desirable that a controller device with tactile sensors be relatively simple and reliable, that the controller device does not require finger repositioning or frequent cleaning and maintenance, that the controller device have no moving parts and no requirement for mechanical preloading, and that the controller device be capable of providing for one, two, or three parameter control.